The WaterRower Analog Heart Rate Transmitter Kit (Polar Chest Belt) sends heart rate information to the Analog Heart Rate Receiver Box (required second part of the system, not included in purchase of this item).

The Viper 360 Belt Set is a premium speed-belt system that helps athletes improve sprinting, leaping, and directional quickness. Padded waist belt for comfort. Easily switch between resistance and assistance modes.